Systems and methods for signaling level information in video coding

ABSTRACT

A device may be configured to signal level information according to one or more of the techniques described herein.

TECHNICAL FIELD

This disclosure relates to video coding and more particularly totechniques for signaling level information for coded video.

BACKGROUND ART

Digital video capabilities can be incorporated into a wide range ofdevices, including digital televisions, laptop or desktop computers,tablet computers, digital recording devices, digital media players,video gaming devices, cellular telephones, including so-calledsmartphones, medical imaging devices, and the like. Digital video may becoded according to a video coding standard. Video coding standardsdefine the format of a compliant bitstream encapsulating coded videodata. A compliant bitstream is a data structure that may be received anddecoded by a video decoding device to generate reconstructed video data.Video coding standards may incorporate video compression techniques.Examples of video coding standards include ISO/IEC MPEG-4 Visual andITU-T H.264 (also known as ISO/IEC MPEG-4 AVC) and High-Efficiency VideoCoding (HEVC). HEVC is described in High Efficiency Video Coding (HEVC),Rec. ITU-T H.265, December 2016, which is incorporated by reference, andreferred to herein as ITU-T H.265. Extensions and improvements for ITU-TH.265 are currently being considered for the development of nextgeneration video coding standards. For example, the ITU-T Video CodingExperts Group (VCEG) and ISO/IEC (Moving Picture Experts Group (MPEG)(collectively referred to as the Joint Video Exploration Team (JVET))are working to standardized video coding technology with a compressioncapability that significantly exceeds that of the current HEVC standard.The Joint Exploration Model 7 (JEM 7), Algorithm Description of JointExploration Test Model 7 (JEM 7), ISO/IEC JTC1/SC29/VVG11 Document:JVET-G1001, July 2017, Torino, IT, which is incorporated by referenceherein, describes the coding features that were under coordinated testmodel study by the JVET as potentially enhancing video coding technologybeyond the capabilities of ITU-T H.265. It should be noted that thecoding features of JEM 7 are implemented in JEM reference software. Asused herein, the term JEM may collectively refer to algorithms includedin JEM 7 and implementations of JEM reference software. Further, inresponse to a “Joint Call for Proposals on Video Compression withCapabilities beyond HEVC,” jointly issued by VCEG and MPEG, multipledescriptions of video coding tools were proposed by various groups atthe 10^(th) Meeting of ISO/IEC JTC1/SC29/WG11 16-20 Apr. 2018, SanDiego, Calif. From the multiple descriptions of video coding tools, aresulting initial draft text of a video coding specification isdescribed in “Versatile Video Coding (Draft 1),” 10th Meeting of ISO/IECJTC1/SC29/WG11 16-20 Apr. 2018, San Diego, Calif., documentJVET-J1001-v2, which is incorporated by reference herein, and referredto as JVET-J1001. The current development of a next generation videocoding standard by the VCEG and MPEG is referred to as the VersatileVideo Coding (WC) project. “Versatile Video Coding (Draft 6),” 15thMeeting of ISO/IEC JTC1/SC29/WG11 3-12 Jul. 2019, Gothenburg, SE,document JVET-02001-vE, which is incorporated by reference herein, andreferred to as JVET-02001, represents the current iteration of the drafttext of a video coding specification corresponding to the WC project.

Video compression techniques enable data requirements for storing andtransmitting video data to be reduced. Video compression techniques mayreduce data requirements by exploiting the inherent redundancies in avideo sequence. Video compression techniques may sub-divide a videosequence into successively smaller portions (i.e., groups of pictureswithin a video sequence, a picture within a group of pictures, regionswithin a picture, sub-regions within regions, etc.). Intra predictioncoding techniques (e.g., spatial prediction techniques within a picture)and inter prediction techniques (i.e., inter-picture techniques(temporal)) may be used to generate difference values between a unit ofvideo data to be coded and a reference unit of video data. Thedifference values may be referred to as residual data. Residual data maybe coded as quantized transform coefficients. Syntax elements may relateresidual data and a reference coding unit (e.g., intra-prediction modeindices, and motion information). Residual data and syntax elements maybe entropy coded. Entropy encoded residual data and syntax elements maybe included in data structures forming a compliant bitstream.

SUMMARY OF INVENTION

In one example, a method of signaling level information for video data,the method comprising: signaling a first syntax element indicating aprofile; signaling a second syntax element indicating a context;signaling a third syntax element indicating a level; sending a profiletier level syntax structure including the first syntax element, secondsyntax element and third syntax element, wherein the first syntaxelement, the second syntax element and the third syntax element arelocated on a top of the profile tier level syntax structure, and whereinthe third syntax element immediately follows the second syntax element.

In one example, a method of decoding video data, the method comprising:receiving a profile tier level syntax structure; parsing a first syntaxelement, from the profile tier level syntax structure, indicating aprofile; parsing a second syntax element, from the profile tier levelsyntax structure, indicating a context; and parsing a third syntaxelement, from the profile tier level syntax structure, indicating alevel, wherein the first syntax element, the second syntax element andthe third syntax element are located on a top of the profile tier levelsyntax structure, and wherein the third syntax element immediatelyfollows the second syntax element.

In one example, a device of decoding video data, the device comprisingone or more processors configured to: receive a profile tier levelsyntax structure; parse a first syntax element, from the profile tierlevel syntax structure, indicating a profile; parse a second syntaxelement, from the profile tier level syntax structure, indicating acontext; and parse a third syntax element, from the profile tier levelsyntax structure, indicating a level, wherein the first syntax element,the second syntax element and the third syntax element are located on atop of the profile tier level syntax structure, and wherein the thirdsyntax element immediately follows the second syntax element.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating an example of a system that maybe configured to encode and decode video data according to one or moretechniques of this disclosure.

FIG. 2 is a conceptual diagram illustrating coded video data andcorresponding data structures according to one or more techniques ofthis disclosure.

FIG. 3 is a conceptual diagram illustrating a data structureencapsulating coded video data and corresponding metadata according toone or more techniques of this disclosure.

FIG. 4 is a conceptual drawing illustrating an example of componentsthat may be included in an implementation of a system that may beconfigured to encode and decode video data according to one or moretechniques of this disclosure.

FIG. 5 is a block diagram illustrating an example of a video encoderthat may be configured to encode video data according to one or moretechniques of this disclosure.

FIG. 6 is a block diagram illustrating an example of a video decoderthat may be configured to decode video data according to one or moretechniques of this disclosure.

DESCRIPTION OF EMBODIMENTS

In general, this disclosure describes various techniques for codingvideo data. In particular, this disclosure describes techniques forsignaling level information for coded video data. It should be notedthat although techniques of this disclosure are described with respectto ITU-T H.264, ITU-T H.265, JEM, and JVET-O2001, the techniques of thisdisclosure are generally applicable to video coding. For example, thecoding techniques described herein may be incorporated into video codingsystems, (including video coding systems based on future video codingstandards) including video block structures, intra predictiontechniques, inter prediction techniques, transform techniques, filteringtechniques, and/or entropy coding techniques other than those includedin ITU-T H.265, JEM, and JVET-O2001. Thus, reference to ITU-T H.264,ITU-T H.265, JEM, and/or JVET-O2001 is for descriptive purposes andshould not be construed to limit the scope of the techniques describedherein. Further, it should be noted that incorporation by reference ofdocuments herein is for descriptive purposes and should not be construedto limit or create ambiguity with respect to terms used herein. Forexample, in the case where an incorporated reference provides adifferent definition of a term than another incorporated referenceand/or as the term is used herein, the term should be interpreted in amanner that broadly includes each respective definition and/or in amanner that includes each of the particular definitions in thealternative.

In one example, a device comprises one or more processors configured tosignal a syntax element indicating a profile corresponding to a codedvideo sequence, signal a syntax element indicating a contextcorresponding to the coded video sequence, and signal a syntax elementindicating a level corresponding to the coded video sequence, whereinthe syntax element indicating the level immediately follows the syntaxelement indicating the context.

In one example, a non-transitory computer-readable storage mediumcomprises instructions stored thereon that, when executed, cause one ormore processors of a device to signal a syntax element indicating aprofile corresponding to a coded video sequence, signal a syntax elementindicating a context corresponding to the coded video sequence, andsignal a syntax element indicating a level corresponding to the codedvideo sequence, wherein the syntax element indicating the levelimmediately follows the syntax element indicating the context.

In one example, an apparatus comprises means for signaling a syntaxelement indicating a profile corresponding to a coded video sequence,means for signaling a syntax element indicating a context correspondingto the coded video sequence, and means for signaling a syntax elementindicating a level corresponding to the coded video sequence, whereinthe syntax element indicating the level immediately follows the syntaxelement indicating the context.

In one example, a device comprises one or more processors configured toparse a syntax element indicating a profile corresponding to a codedvideo sequence, parse a syntax element indicating a contextcorresponding to the coded video sequence, and parse a syntax elementindicating a level corresponding to the coded video sequence, whereinthe syntax element indicating the level immediately follows the syntaxelement indicating the context.

In one example, a non-transitory computer-readable storage mediumcomprises instructions stored thereon that, when executed, cause one ormore processors of a device to parse a syntax element indicating aprofile corresponding to a coded video sequence, parse a syntax elementindicating a context corresponding to the coded video sequence, andparse a syntax element indicating a level corresponding to the codedvideo sequence, wherein the syntax element indicating the levelimmediately follows the syntax element indicating the context.

In one example, an apparatus comprises means for parsing a syntaxelement indicating a profile corresponding to a coded video sequence,means for parsing a syntax element indicating a context corresponding tothe coded video sequence, and means for parsing a syntax elementindicating a level corresponding to the coded video sequence, whereinthe syntax element indicating the level immediately follows the syntaxelement indicating the context.

The details of one or more examples are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages will be apparent from the description and drawings, and fromthe claims.

Video content includes video sequences comprised of a series of frames(or pictures). A series of frames may also be referred to as a group ofpictures (GOP). Each video frame or picture may be divided into one ormore regions. Regions may be defined according to a base unit (e.g., avideo block) and sets of rules defining a region. For example, a ruledefining a region may be that a region must be an integer number ofvideo blocks arranged in a rectangle. Further, video blocks in a regionmay be ordered according to a scan pattern (e.g., a raster scan). Asused herein, the term video block may generally refer to an area of apicture or may more specifically refer to the largest array of samplevalues that may be predictively coded, sub-divisions thereof, and/orcorresponding structures. Further, the term current video block mayrefer to an area of a picture being encoded or decoded. A video blockmay be defined as an array of sample values. It should be noted that insome cases pixel values may be described as including sample values forrespective components of video data, which may also be referred to ascolor components, (e.g., luma (Y) and chroma (Cb and Cr) components orred, green, and blue components). It should be noted that in some cases,the terms pixel value and sample value are used interchangeably.Further, in some cases, a pixel or sample may be referred to as a pel. Avideo sampling format, which may also be referred to as a chroma format,may define the number of chroma samples included in a video block withrespect to the number of luma samples included in a video block. Forexample, for the 4:2:0 sampling format, the sampling rate for the lumacomponent is twice that of the chroma components for both the horizontaland vertical directions.

A video encoder may perform predictive encoding on video blocks andsub-divisions thereof. Video blocks and sub-divisions thereof may bereferred to as nodes. ITU-T H.264 specifies a macroblock including 16×16luma samples. That is, in ITU-T H.264, a picture is segmented intomacroblocks. ITU-T H.265 specifies an analogous Coding Tree Unit (CTU)structure (which may be referred to as a largest coding unit (LCU)). InITU-T H.265, pictures are segmented into CTUs. In ITU-T H.265, for apicture, a CTU size may be set as including 16×16, 32×32, or 64×64 lumasamples. In ITU-T H.265, a CTU is composed of respective Coding TreeBlocks (CTB) for each component of video data (e.g., luma (Y) and chroma(Cb and Cr). It should be noted that video having one luma component andthe two corresponding chroma components may be described as having twochannels, i.e., a luma channel and a chroma channel. Further, in ITU-TH.265, a CTU may be partitioned according to a quadtree (QT)partitioning structure, which results in the CTBs of the CTU beingpartitioned into Coding Blocks (CB). That is, in ITU-T H.265, a CTU maybe partitioned into quadtree leaf nodes. According to ITU-T H.265, oneluma CB together with two corresponding chroma CBs and associated syntaxelements are referred to as a coding unit (CU). In ITU-T H.265, aminimum allowed size of a CB may be signaled. In ITU-T H.265, thesmallest minimum allowed size of a luma CB is 8×8 luma samples. In ITU-TH.265, the decision to code a picture area using intra prediction orinter prediction is made at the CU level.

In ITU-T H.265, a CU is associated with a prediction unit (PU) structurehaving its root at the CU. In ITU-T H.265, PU structures allow luma andchroma CBs to be split for purposes of generating correspondingreference samples. That is, in ITU-T H.265, luma and chroma CBs may besplit into respective luma and chroma prediction blocks (PBs), where aPB includes a block of sample values for which the same prediction isapplied. In ITU-T H.265, a CB may be partitioned into 1, 2, or 4 PBs.ITU-T H.265 supports PB sizes from 64×64 samples down to 4×4 samples. InITU-T H.265, square PBs are supported for intra prediction, where a CBmay form the PB or the CB may be split into four square PBs. In ITU-TH.265, in addition to the square PBs, rectangular PBs are supported forinter prediction, where a CB may by halved vertically or horizontally toform PBs. Further, it should be noted that in ITU-T H.265, for interprediction, four asymmetric PB partitions are supported, where the CB ispartitioned into two PBs at one quarter of the height (at the top or thebottom) or width (at the left or the right) of the CB. Intra predictiondata (e.g., intra prediction mode syntax elements) or inter predictiondata (e.g., motion data syntax elements) corresponding to a PB is usedto produce reference and/or predicted sample values for the PB.

JEM specifies a CTU having a maximum size of 256×256 luma samples. JEMspecifies a quadtree plus binary tree (QTBT) block structure. In JEM,the QTBT structure enables quadtree leaf nodes to be further partitionedby a binary tree (BT) structure. That is, in JEM, the binary treestructure enables quadtree leaf nodes to be recursively dividedvertically or horizontally. In JVET-O2001, CTUs are partitionedaccording a quadtree plus multi-type tree (QTMT or QT+MTT) structure.The QTMT in JVET-O2001 is similar to the QTBT in JEM. However, inJVET-O2001, in addition to indicating binary splits, the multi-type treemay indicate so-called ternary (or triple tree (TT)) splits. A ternarysplit divides a block vertically or horizontally into three blocks. Inthe case of a vertical TT split, a block is divided at one quarter ofits width from the left edge and at one quarter its width from the rightedge and in the case of a horizontal TT split a block is at one quarterof its height from the top edge and at one quarter of its height fromthe bottom edge.

As described above, each video frame or picture may be divided into oneor more regions. For example, according to ITU-T H.265, each video frameor picture may be partitioned to include one or more slices and furtherpartitioned to include one or more tiles, where each slice includes asequence of CTUs (e.g., in raster scan order) and where a tile is asequence of CTUs corresponding to a rectangular area of a picture. Itshould be noted that a slice, in ITU-T H.265, is a sequence of one ormore slice segments starting with an independent slice segment andcontaining all subsequent dependent slice segments (if any) that precedethe next independent slice segment (if any). A slice segment, like aslice, is a sequence of CTUs. Thus, in some cases, the terms slice andslice segment may be used interchangeably to indicate a sequence of CTUsarranged in a raster scan order. Further, it should be noted that inITU-T H.265, a tile may consist of CTUs contained in more than one sliceand a slice may consist of CTUs contained in more than one tile.However, ITU-T H.265 provides that one or both of the followingconditions shall be fulfilled: (1) All CTUs in a slice belong to thesame tile; and (2) All CTUs in a tile belong to the same slice.

With respect to JVET-O2001, slices are required to consist of an integernumber of bricks instead of only being required to consist of an integernumber of CTUs. In JVET-O2001, a brick is a rectangular region of CTUrows within a particular tile in a picture. Further, in JVET-O2001, atile may be partitioned into multiple bricks, each of which consistingof one or more CTU rows within the tile. A tile that is not partitionedinto multiple bricks is also referred to as a brick. However, a brickthat is a true subset of a tile is not referred to as a tile. As such, aslice including a set of CTUs which do not form a rectangular region ofa picture may or may not be supported in some video coding techniques.Further, it should be noted that in some cases, a slice may be requiredto consist of an integer number of complete tiles and in this case isreferred to as a tile group. The techniques described herein mayapplicable to bricks, slices, tiles, and/or tile groups. FIG. 2 is aconceptual diagram illustrating an example of a group of picturesincluding slices. In the example illustrated in FIG. 2, Pica isillustrated as including two slices (i.e., Slice₀ and Slice₁). In theexample illustrated in FIG. 2, Slice₀ includes one brick, i.e., Brick₀and Slice₁ includes two bricks, i.e., Brick₁ and Brick₂. It should benoted that in some cases, Slice₀ and Slice₁ may meet the requirements ofand be classified as tiles and/or tile groups.

For intra prediction coding, an intra prediction mode may specify thelocation of reference samples within a picture. In ITU-T H.265, definedpossible intra prediction modes include a planar (i.e., surface fitting)prediction mode, a DC (i.e., flat overall averaging) prediction mode,and 33 angular prediction modes (predMode: 2-34). In JEM, definedpossible intra-prediction modes include a planar prediction mode, a DCprediction mode, and 65 angular prediction modes. It should be notedthat planar and DC prediction modes may be referred to asnon-directional prediction modes and that angular prediction modes maybe referred to as directional prediction modes. It should be noted thatthe techniques described herein may be generally applicable regardlessof the number of defined possible prediction modes.

For inter prediction coding, a reference picture is determined and amotion vector (MV) identifies samples in the reference picture that areused to generate a prediction for a current video block. For example, acurrent video block may be predicted using reference sample valueslocated in one or more previously coded picture(s) and a motion vectoris used to indicate the location of the reference block relative to thecurrent video block. A motion vector may describe, for example, ahorizontal displacement component of the motion vector (i.e., MVO, avertical displacement component of the motion vector (i.e., MVO, and aresolution for the motion vector (e.g., one-quarter pixel precision,one-half pixel precision, one-pixel precision, two-pixel precision,four-pixel precision). Previously decoded pictures, which may includepictures output before or after a current picture, may be organized intoone or more to reference pictures lists and identified using a referencepicture index value. Further, in inter prediction coding, uni-predictionrefers to generating a prediction using sample values from a singlereference picture and bi-prediction refers to generating a predictionusing respective sample values from two reference pictures. That is, inuni-prediction, a single reference picture and corresponding motionvector are used to generate a prediction for a current video block andin bi-prediction, a first reference picture and corresponding firstmotion vector and a second reference picture and corresponding secondmotion vector are used to generate a prediction for a current videoblock. In bi-prediction, respective sample values are combined (e.g.,added, rounded, and clipped, or averaged according to weights) togenerate a prediction. Pictures and regions thereof may be classifiedbased on which types of prediction modes may be utilized for encodingvideo blocks thereof. That is, for regions having a B type (e.g., a Bslice), bi-prediction, uni-prediction, and intra prediction modes may beutilized, for regions having a P type (e.g., a P slice), uni-prediction,and intra prediction modes may be utilized, and for regions having an Itype (e.g., an I slice), only intra prediction modes may be utilized. Asdescribed above, reference pictures are identified through referenceindices. For example, for a P slice, there may be a single referencepicture list, RefPicList0 and for a B slice, there may be a secondindependent reference picture list, RefPicList1, in addition toRefPicList0. It should be noted that for uni-prediction in a B slice,one of RefPicList0 or RefPicList1 may be used to generate a prediction.Further, it should be noted that during the decoding process, at theonset of decoding a picture, reference picture list(s) are generatedfrom previously decoded pictures stored in a decoded picture buffer(DPB).

Further, a coding standard may support various modes of motion vectorprediction. Motion vector prediction enables the value of a motionvector for a current video block to be derived based on another motionvector. For example, a set of candidate blocks having associated motioninformation may be derived from spatial neighboring blocks and temporalneighboring blocks to the current video block. Further, generated (ordefault) motion information may be used for motion vector prediction.Examples of motion vector prediction include advanced motion vectorprediction (AMVP), temporal motion vector prediction (TMVP), so-called“merge” mode, and “skip” and “direct” motion inference. Further, otherexamples of motion vector prediction include advanced temporal motionvector prediction (ATMVP) and Spatial-temporal motion vector prediction(STMVP). For motion vector prediction, both a video encoder and videodecoder perform the same process to derive a set of candidates. Thus,for a current video block, the same set of candidates is generatedduring encoding and decoding.

As described above, for inter prediction coding, reference samples in apreviously coded picture are used for coding video blocks in a currentpicture. Previously coded pictures which are available for use asreference when coding a current picture are referred as referencepictures. It should be noted that the decoding order does not necessarycorrespond with the picture output order, i.e., the temporal order ofpictures in a video sequence. In ITU-T H.265, when a picture is decodedit is stored to a decoded picture buffer (DPB) (which may be referred toas frame buffer, a reference buffer, a reference picture buffer, or thelike). In ITU-T H.265, pictures stored to the DPB are removed from theDPB when they been output and are no longer needed for coding subsequentpictures. In ITU-T H.265, a determination of whether pictures should beremoved from the DPB is invoked once per picture, after decoding a sliceheader, i.e., at the onset of decoding a picture. For example, referringto FIG. 2, Pic₃ is illustrated as referencing Pic₂. Similarly, Pic₄ isillustrated as referencing Pic₁. With respect to FIG. 2 assuming thepicture number corresponds to the decoding order the DPB would bepopulated as follows: after decoding Pic₁, the DPB would include {Pica};at the onset of decoding Pic₂, the DPB would include {Pic₁}; afterdecoding Pic₂, the DPB would include {Pic₁, Pic₂}; at the onset ofdecoding Pic₃, the DPB would include {Pic₁, Pic₂}. Pic₃ would then bedecoded with reference to Pic₂ and after decoding Pic₃, the DPB wouldinclude {Pic₁, Pic₂, Pica}. At the onset of decoding Pic₄, pictures Pic₂and Pic₃ would be marked for removal from the DPB, as they are notneeded for decoding Pic₄ (or any subsequent pictures, not shown) andassuming Pic₂ and Pic₃ have been output, the DPB would be updated toinclude {Pic₁}. Pic₄ would then be decoded with referencing Pic₁. Theprocess of marking pictures for removal from a DPB may be referred to asreference picture set (RPS) management.

As described above, intra prediction data or inter prediction data isused to produce reference sample values for a block of sample values.The difference between sample values included in a current PB, oranother type of picture area structure, and associated reference samples(e.g., those generated using a prediction) may be referred to asresidual data. Residual data may include respective arrays of differencevalues corresponding to each component of video data. Residual data maybe in the pixel domain. A transform, such as, a discrete cosinetransform (DCT), a discrete sine transform (DST), an integer transform,a wavelet transform, or a conceptually similar transform, may be appliedto an array of difference values to generate transform coefficients. Itshould be noted that in ITU-T H.265 and JVET-O2001, a CU is associatedwith a transform unit (TU) structure having its root at the CU level.That is, an array of difference values may be partitioned for purposesof generating transform coefficients (e.g., four 8×8 transforms may beapplied to a 16×16 array of residual values). For each component ofvideo data, such sub-divisions of difference values may be referred toas Transform Blocks (TBs). It should be noted that in some cases, a coretransform and a subsequent secondary transforms may be applied (in thevideo encoder) to generate transform coefficients. For a video decoder,the order of transforms is reversed.

A quantization process may be performed on transform coefficients orresidual sample values directly (e.g., in the case, of palette codingquantization). Quantization approximates transform coefficients byamplitudes restricted to a set of specified values. Quantizationessentially scales transform coefficients in order to vary the amount ofdata required to represent a group of transform coefficients.Quantization may include division of transform coefficients (or valuesresulting from the addition of an offset value to transformcoefficients) by a quantization scaling factor and any associatedrounding functions (e.g., rounding to the nearest integer). Quantizedtransform coefficients may be referred to as coefficient level values.Inverse quantization (or “dequantization”) may include multiplication ofcoefficient level values by the quantization scaling factor, and anyreciprocal rounding or offset addition operations. It should be notedthat as used herein the term quantization process in some instances mayrefer to division by a scaling factor to generate level values andmultiplication by a scaling factor to recover transform coefficients insome instances. That is, a quantization process may refer toquantization in some cases and inverse quantization in some cases.Further, it should be noted that although in some of the examples belowquantization processes are described with respect to arithmeticoperations associated with decimal notation, such descriptions are forillustrative purposes and should not be construed as limiting. Forexample, the techniques described herein may be implemented in a deviceusing binary operations and the like. For example, multiplication anddivision operations described herein may be implemented using bitshifting operations and the like.

Quantized transform coefficients and syntax elements (e.g., syntaxelements indicating a coding structure for a video block) may be entropycoded according to an entropy coding technique. An entropy codingprocess includes coding values of syntax elements using lossless datacompression algorithms. Examples of entropy coding techniques includecontent adaptive variable length coding (CAVLC), context adaptive binaryarithmetic coding (CABAC), probability interval partitioning entropycoding (PIPE), and the like. Entropy encoded quantized transformcoefficients and corresponding entropy encoded syntax elements may forma compliant bitstream that can be used to reproduce video data at avideo decoder. An entropy coding process, for example, CABAC, mayinclude performing a binarization on syntax elements. Binarizationrefers to the process of converting a value of a syntax element into aseries of one or more bits. These bits may be referred to as “bins.”Binarization may include one or a combination of the following codingtechniques: fixed length coding, unary coding, truncated unary coding,truncated Rice coding, Golomb coding, k-th order exponential Golombcoding, and Golomb-Rice coding. For example, binarization may includerepresenting the integer value of 5 for a syntax element as 00000101using an 8-bit fixed length binarization technique or representing theinteger value of 5 as 11110 using a unary coding binarization technique.As used herein each of the terms fixed length coding, unary coding,truncated unary coding, truncated Rice coding, Golomb coding, k-th orderexponential Golomb coding, and Golomb-Rice coding may refer to generalimplementations of these techniques and/or more specific implementationsof these coding techniques. For example, a Golomb-Rice codingimplementation may be specifically defined according to a video codingstandard. In the example of CABAC, for a particular bin, a contextprovides a most probable state (MPS) value for the bin (i.e., an MPS fora bin is one of 0 or 1) and a probability value of the bin being the MPSor the least probably state (LPS). For example, a context may indicate,that the MPS of a bin is 0 and the probability of the bin being 1 is0.3. It should be noted that a context may be determined based on valuesof previously coded bins including bins in the current syntax elementand previously coded syntax elements. For example, values of syntaxelements associated with neighboring video blocks may be used todetermine a context for a current bin.

[Object 1]

-   -   With respect to the equation's used herein She following        arithmetic operators, may be used:    -   + Addition    -   − Subtraction    -   * Multiplication, including matrix multiplication    -   x^(y) Exponentiation Specifies x to the power of y. In other        contexts, such notation is used for superscripting not intended        for interpretation as exponentiation.    -   / Integer division with truncation of the result toward zero.        For example, 7/4 and −7/−4 are truncated to 1 and −7/4 and 7/−4        are truncated to −1.    -   + Used to denote division in mathematical equations where no        truncation or rounding is intended.

$\frac{x}{y}$

Used to denote in mathematical equations where no truncation or roundingis intended.

[Object 2]

-   -   Further, the following mathematical functions may be used:        -   Log 2(x) the base-2 logarithm of x;

${{Min}\left( {x,y} \right)} = \left\{ {\begin{matrix}x & ; & {x<=y} \\y & ; & {x > y}\end{matrix};{{{Max}\left( {x,y} \right)} = \left\{ \begin{matrix}x & ; & {x>=y} \\y & ; & {x < y}\end{matrix} \right.}} \right.$

-   -   -   Ceil(x) the smallest integer greater than or equal to x.

[Object 3]

-   -   With respect to tire example syntax used herein, the following        definitions of logical operators may be applied:        -   x && y Boolean logical “and” of x and y        -   x∥y Boolean logical “or” of x and y        -   ! Boolean logical “not”        -   x?y: z If x is TRUE or not equal to 0, evaluates to the            value of y, otherwise, evaluates to the value of z.

[Object 4]

-   -   Further, the following relational operators may be applied.        -   >Greater than        -   >=Greater than or equal to        -   <Less than        -   <=Less than or equal to        -   ==Equal to        -   !=Not equal to

[Object 5]

-   -   Further, is should be rioted shat m the syntax descriptors used        herein, the following descriptor's may be applied        -   b(8): byte haring any pattern of bit string (8 bits). The            parsing process for this descriptor is specified by the            return value of the function read_bits(8).        -   f(n) fixed-pattern bit siring using n bits written (from            left to right) with the left bis first. The parsing process            for this descriptor is specified by the return value of the            function read_bits(n)        -   se(v): signed integer 0-th order Exp-Golomb-coded syntax            element with the left bit first        -   tb(v): truncated binary using up to maxVal bits with maxVal            defined in die semantics of the symtax element.        -   tn(v): truncated unary using up to maxVal bits with maxVal            defined in the semantics of die symtax element.        -   u(n) unsigned integer using n bits. When n is “v” in the            syntax table, the number of bits varies in a manner            dependent on the value of other syntax elements. The passing            process for this descriptor is specified by the return value            of the function read_bits(n) interpreted as a binary            representation of an unsigned integer with most significant            bit written first.        -   ue(t): unsigned integer 0-th order Exp-Golomb-coded syntax            element with the left bit first.

As described above, video content includes video sequences comprised ofa series of frames (or pictures) and each video frame or picture may bedivided into one or more regions. A coded video sequence (CVS) may beencapsulated (or structured) as a sequence of access units, where eachaccess unit includes video data structured as network abstraction layer(NAL) units. It should be noted that in some cases, an access unit maybe required to contain exactly one coded picture. A bitstream may bedescribed as including a sequence of NAL units forming one or more CVSs.It should be noted that multi-layer extensions enable a videopresentation to include a base layer and one or more additionalenhancement layers. For example, a base layer may enable a videopresentation having a basic level of quality (e.g., a High Definitionrendering and/or a 30 Hz frame rate) to be presented and an enhancementlayer may enable a video presentation having an enhanced level ofquality (e.g., an Ultra High Definition rendering and/or a 60 Hz framerate) to be presented. An enhancement layer may be coded by referencinga base layer. That is, for example, a picture in an enhancement layermay be coded (e.g., using inter-layer prediction techniques) byreferencing one or more pictures (including scaled versions thereof) ina base layer. Each NAL unit may include an identifier indicating a layerof video data the NAL unit is associated with. It should be noted thatsub-bitstream extraction may refer to a process where a device receivinga compliant or conforming bitstream forms a new compliant or conformingbitstream by discarding and/or modifying data in the received bitstream.For example, sub-bitstream extraction may be used to form a newcompliant or conforming bitstream corresponding to a particularrepresentation of video (e.g., a high quality representation). Layersmay also be coded independent of each other. In this case, there may notbe an inter-layer prediction between two layers.

Referring to the example illustrated in FIG. 2, each slice of video dataincluded in Pica (i.e., Slice₀ and Slice₁) is illustrated as beingencapsulated in a NAL unit. In JVET-O2001, each of a video sequence, aGOP, a picture, a slice, and CTU may be associated with metadata thatdescribes video coding properties. JVET-O2001 defines parameters setsthat may be used to describe video data and/or video coding properties.In particular, JVET-O2001 includes the following five types of parametersets: decoding parameter set (DPS), video parameter set (VPS), sequenceparameter set (SPS), picture parameter set (PPS), and adaption parameterset (APS). In JVET-O2001, parameter sets may be encapsulated as aspecial type of NAL unit or may be signaled as a message. NAL unitsincluding coded video data (e.g., a slice) may be referred to as VCL(Video Coding Layer) NAL units and NAL units including metadata (e.g.,parameter sets) may be referred to as non-VCL NAL units. Further,JVET-O2001 enables supplemental enhancement information (SEI) messagesto be signaled. In JVET-O2001, SEI messages assist in processes relatedto decoding, display or other purposes, however, SEI messages may not berequired for constructing the luma or chroma samples by the decodingprocess. In JVET-O2001, SEI messages may be signaled in a bitstreamusing non-VCL NAL units. Further, SEI messages may be conveyed by somemeans other than by being present in the bitstream (i.e., signaledout-of-band).

[Object 6]

-   -   An access unit may be called a layer access unit. As described        above, multi-layer extensions enable a video presentation to        include a base layer and one or more additional enhancement        layers. It should be noted that in ITU-T H.265 a temporal true        subset of a scalable layer is not referred to as a layer but        referred to as a sub-layer or temporal sub-layer. That is, ITU-T        H.26S protides the following definition with respect to        sub-layers:    -   sub-layer A temporal scalable layer of a temporal scalable        bitstream, consisting of VCL NAL units with a particular value        of the TemporalId variable and the associated non-VCL NAL units

[Object 7]

-   -   It should be noted that JVET-O2001 provides the following        definitions with respect to sub-layers.    -   sub-layer: A temporal scalable layer of a temporal scalable        bitstream, consisting of VCL NAL units with a particular value        of the TemporalId variable and the associated non-VCL NAL units.    -   sub-layer representation: A subset of the bitstream consisting        of NAL units of a particular sub-laser and the lower sub-layers.

It should be noted that, in general, the terms temporal sub-layer,sub-layer and sub-layer representation may be used interchangeably.

FIG. 3 illustrates an example of a bitstream including multiple CVSs,where a CVS is represented by NAL units included in a respective accessunit. In the example illustrated in FIG. 3, non-VCL NAL units includerespective parameter set NAL units (i.e., Sequence Parameter Sets (SPS),and Picture Parameter Set (PPS) NAL units), an SEI message NAL unit, andan access unit delimiter NAL unit. It should be noted that in FIG. 3,HEADER is a NAL unit header. JVET-O2001 defines NAL unit headersemantics that specify the type of Raw Byte Sequence Payload (RBSP) datastructure included in the NAL unit.

[Object 8]

-   -   As described above, JVET-O2001 includes, a decoding parameter        set (DPS) and an Sequence Parameter Set (SPS) In JVET-O2001, the        DPS and SPS include a syntax structure, called        profile_tier_level( ), for indicating the capabilities required        to decode the Coded Video Sequence. The profile_tier_level( )        syntax structure includes the general profile her and level of        the Coded Video Sequence and may also include information about        sub-profiles and sub-layer levels. As provided below, through a        syntax element called num_sub_profiles, it is possible to        indicate hew many sub-profiles will be signaled. For each such        signaled sub-profile, there is a 32-bit long syntax element        indicating the value of that sub-profile. As provided below, in        JVET-O2001, an 8-bit value is signaled for num_sub_profiles with        no further constraints on the value range, resulting in an        implicit value range of 0 to 255 inclusive.

[Object 9]

-   -   Table 1 illustrates the syntax of the DPS provided in        JVET-O2001.

TABLE 1 Descriptor decoding_parameter_set_rbsp( ) { dps_decoding_parameter_set_id u(4)  dps_max_sub_layers_minus1 u(3) dps_reserved_zero_bit u(1)  profile_tier_level(dps_max_sub_layers_minus1 )  dps_extension_flag u(1)  if(dps_extension_flag )   while( more_rbsp_data( ) )   dps_extension_data_flag u(1)  rbsp_trailing_bits( ) }

[Object 10]

-   -   With respect to Table 1. JVET-O200 provides the following        semantics:    -   A DPS RBSP shall be available to the decoding process prior to        it being referred, included in at least one access unit with        TemporalId equal to 0 or provided through external means, said        the DPS NAL unis containing die DPS RBSP shall have nuh_layer_id        equal so the nuh_layer_id of the SPS NAL unit that refers to it.    -   NOTE—DPS NAL units are required to be available to the decoding        process prior to their being referred (either in die bitstream        or by external means). However, the DPS RBSP contains        information that is not necessary for operation of die decoding        process specified in clauses 2 through 10 of tins Specification.    -   dps_decoding_parameter_set_id identifies die DPS for reference        by other syntax elements. The value of        dps_decoding_parameter_set_id shall not be equal to 0.    -   dps_max_sub_layers_minus1 plus 1 specifies the maximum number of        temporal sub-layers, that may be present in each CVS referring        to the DPS. The value of dps_max_sub_layers_minus1 shall be in        the range of 0 to 6, inclusive.    -   dps_reserved_zero_bit shall be equal to 0 in bitstreams        conforming to this version of tins Specification. The value 0        tor dps_reserved_zero_bit is reserved for future use by        ITU-T|TSO/IEC.

[Object 11]

-   -   dps_extension_flag equal to 0 specifies that no        dps_extension_data_flag_syntax elements are present in the DPS        RBSP syntax structure. dps_extension_flag equal to 1 specifics        that there are dps_extension_data_flag syntax elements present        in the DPS RBSP syntax structure.    -   dps_extension_data_flag may have any value. Its presence and        value do trot affect decoder conformance to profiles specified        in Annex A. Decoders conforming to tins version of this        Specification shall ignore all dps_extension_data_flag syntax        elements

[Object 12]

-   -   As illustrated in Table 1, the DPS provided in JVET-O2001        includes die profile_tier_level( ) syntax structure. Tire        profile_tier_level( ) syntax structure is described in further        detail below. In JVET-O2001 the a Sequence parameter set (SPS)        also includes the profile_tier_level( ) syntax structure Table 3        illustrates the relevant portion of the syntax structure of the        SPS provided in TVBT-O2001 including the profile_tier_level( )        syntax structure

TABLE 3 Descriptor seq_parameter_set_rbsp( ) { sps_decoding_parameter_set_id u(4)  sps_video_parameter_set_id u(4) sps_max_sub_layers_minus1 u(3)  sps_reserved_zero_5bits u(5) profile_tier_level( sps_max_sub_layers_minus1 ) ... }

[Object 13]

-   -   With respect to Table 3, JVET-O2001 provides the following        semantics:    -   An SPS RBSP shall be available to the decoding process prior to        it being referred, included in at least one access unit with        TemporalId equal to 0 or provided through external means, and        the SPS NAL unit containing the SPS RBSP shall have muh_layer_id        equal to the nuh_layer_id of PPS NAL unit that refers to it.    -   All SPS NAL units with a particular value of        sps_seq_parameter_set_id us a CVS shall have the same content.    -   sps_decoding_parameter_set_id, when greater than 0, specifies        site value of dps_decoding_parameter_set_id for the DPS referred        to by the SPS. When sps_decoding_parameter_set_id is equal to 0        the SPS does not refer to a DPS and no DPS is referred to when        decoding each CVS referring to the SPS. The value of        sps_decoding_parameter_set_id shall be the same in all SPSs that        are referred to by coded pictures in a bitstream.    -   sps_video_parameter_set_id, when greater than 0, specifies the        value of vps_video_parameter_set_id for the VPS referred to by        the SPS. When sps_video_parameter_set_id is equal to 0, the SPS        does not refer to a VPS and no VPS is referred to when decoding        each CVS referring to the SPS    -   sps_max_sub_layers_minus1 plus 1 specifies the maximum number of        temporal sub-layers that may be present in each CVS referring to        the SPS. The value of sps_max_sub_layers_minus1 shall be in the        range of 0 to 6, inclusive.

[Object 14]

-   -   sps_reserved_zero_5bits shall be equal to 0 in bitstreams        conforming to tins version of this Specification. Other values        for sps_reserved_zero_5bits are reserved for future use by        ITU-T|ISO/TEC.

[Object 15]

-   -   Table 4 illustrates the profile_tier_level( ) syntax structure        provided in JVET-O2001.

TABLE 4 Descriptor profile_tier_level( sps_max_sub_layers_minus1 ) { general_profile_idc u(7)  general_tier_flag u(1)  num_sub_profiles u(8) for( i = 0; 1 <= num_sub_profiles; i++ )   general_sub_profiles_idc[ i]  u(32)  general_constraint_info( )  general_level_idc u(8)  for( i =0; i < maxNumSubLayersMinus1; i++ )   sub_layer_level_present_flag[ i ]u(1)  while( !byte_aligned( ) )   ptl_alignment_zero_bit f(1)  for( i =0; i < maxNumSubLayersMinus1; i++ )   if( sub_layer_level_present_flag[i ] )    sub_layer_level_idc[ i ] u(8) }

[Object 16]

-   -   JVET-O2001 provides the following definitions for the respective        syntax elements illustrated in Table 4.    -   When tire profile_tier_level( ) structure is included in a DPS,        the BitstreamInScope is the entire bitstream that refers to the        DPS. When the profile_tier_level( ) structure is included in an        SPS, the BitstreamInScope is the CVS that refers to the SPS.    -   general_profile_idc indicates s profile to which        BitstreamInScope conforms as specified in Annex A Bitstreams        shall not contain values of general_profile_idc other than those        specified in Annex A. Other values of general_profile_idc are        reserved for future use by ITU-T|ISO/TEC.    -   general_tier_flag specifies the tier context for the        interpretation of general_level_idc as specified in Annex A.    -   num_sub_profiles specifies the number of the        general_sub_profile_idc[i] syntax elements.    -   general_sub_profile_idc[i] Indicates the i-th interoperability        metadata registered as specified by X Recommendation ITU-T T.35,        the contents of winch are not specified in this Specification

[Object 17]

-   -   general_level_idc indicate a level to which BitstreamInScope        conforms as specified in Annex A. Bitstreams shall nor contain        values of general_level_idc other than those specified in        Annex A. Other values of general_level_idc are reserved for        future use by ITU-T|ISO/IEC.    -   NOTE—A greater value of general_level_idc indicates a higher        level. The maximum level signalled in the DPS for        BitstreamInScope may be higher than the level signalled in the        SPS for a CVS contained within BitstreamInScope.    -   NOTE—When BitstreamInScope conforms to multiple profiles        general_profile_idc should indicate the profile that provides        the preferred decoded result or the preferred bitstream        identification, as determined by the encoder (in a manner not        specified in this Specification).    -   NOTE—When the profile_tier_level( ) syntax structure is included        in a DPS and CVSs of BitstreamInScope conform to different        profiles, general_profile_idc and level_idc should indicate the        profile and level for a decoder that is capable of decoding        BitstreamInScope.    -   sub_layer_level_present_flag[i] equal to 1 specifies that level        information is present in the profile_tier_level( ) syntax        structure for die sub-layer representation with TemporalId equal        to i. sub_layer_level_present_flag[i] equal to 0 specifies that        level information is not present in the profile_tier_level( )        syntax structure for the sub-layer representation with        TemporalId equal to i.    -   ptf_alignment_zero_bits shall be equal to 0    -   The semantics of the syntax element sub_layer_level_idc[i] is,        apart from the specific anon of the inference of not present        values, the same as the syntax element general_ievel_idc, but        apply to the sub-laser representation with TemporalId equal to        i.

It should be noted that although the semantics of some syntax elementsabove include reference to Annex A with respect to profiles, levels, andtiers, JVET-O2001 does not define an Annex A. Examples of profiles,levels, and tiers are provided below with respect to Table 5. Further,with respect to Table 4, it should be noted that thegeneral_constraint_info( ) syntax structure is a fixed length syntaxstructure essentially including a series of flags indicating respectiveconstraints. For the sake of brevity, the general_constraint_info( )syntax structure is not provided herein, however, reference is made tothe relevant sections of JVET-O2001.

[Object 18]

-   -   As provided above, in JVET-O2001, the general level is signaled        via the syntax element general_level_idc after the information        about sub-profile(s). Also general_constraint_info( ) is        signalled after the information about sub-profiler(s) In order        for a decoder, or any other type of bitstream parser (such as an        analyzer, packetizer, transcoder, extractor, rewriter) to        determine the level of the Coded Video Sequence, it would be        required to parse the value of num_sub_profiles and use that        value to determine the location of the general_level_idc syntax        element. Thus, the value of the general_level_idc can be        retrieved either through processing through N 32-bit syntax        elements (i.e., N instances of syntax element        general_sub_profile_idc) or through jumping forward N×32 bits        after parsing num_sub_profiles (where N=num_sub_profiles).        Accordingly, determining die level that the Coded Video Sequence        conforms to requires parsing that involves logic for conditional        parsing based on the value of an earlier syntax element. Tins        may be less than ideal. This disclosure describes techniques for        signaling of profile, tier, level, constraint information, and        sub-profile, which simplify the parsing the level information        and in some examples, enable parsing the level information        without parsing any conditionally present syntax elements.

FIG. 1 is a block diagram illustrating an example of a system that maybe configured to code (i.e., encode and/or decode) video data accordingto one or more techniques of this disclosure. System 100 represents anexample of a system that may encapsulate video data according to one ormore techniques of this disclosure. As illustrated in FIG. 1, system 100includes source device 102, communications medium 110, and destinationdevice 120. In the example illustrated in FIG. 1, source device 102 mayinclude any device configured to encode video data and transmit encodedvideo data to communications medium 110. Destination device 120 mayinclude any device configured to receive encoded video data viacommunications medium 110 and to decode encoded video data. Sourcedevice 102 and/or destination device 120 may include computing devicesequipped for wired and/or wireless communications and may include, forexample, set top boxes, digital video recorders, televisions, desktop,laptop or tablet computers, gaming consoles, medical imagining devices,and mobile devices, including, for example, smartphones, cellulartelephones, personal gaming devices.

Communications medium 110 may include any combination of wireless andwired communication media, and/or storage devices. Communications medium110 may include coaxial cables, fiber optic cables, twisted pair cables,wireless transmitters and receivers, routers, switches, repeaters, basestations, or any other equipment that may be useful to facilitatecommunications between various devices and sites.

Communications medium 110 may include one or more networks. For example,communications medium 110 may include a network configured to enableaccess to the World Wide Web, for example, the Internet. A network mayoperate according to a combination of one or more telecommunicationprotocols. Telecommunications protocols may include proprietary aspectsand/or may include standardized telecommunication protocols. Examples ofstandardized telecommunications protocols include Digital VideoBroadcasting (DVB) standards, Advanced Television Systems Committee(ATSC) standards, Integrated Services Digital Broadcasting (ISDB)standards, Data Over Cable Service Interface Specification (DOCSIS)standards, Global System Mobile Communications (GSM) standards, codedivision multiple access (CDMA) standards, 3rd Generation PartnershipProject (3GPP) standards, European Telecommunications StandardsInstitute (ETSI) standards, Internet Protocol (IP) standards, WirelessApplication Protocol (WAP) standards, and Institute of Electrical andElectronics Engineers (IEEE) standards.

Storage devices may include any type of device or storage medium capableof storing data. A storage medium may include a tangible ornon-transitory computer-readable media. A computer readable medium mayinclude optical discs, flash memory, magnetic memory, or any othersuitable digital storage media. In some examples, a memory device orportions thereof may be described as non-volatile memory and in otherexamples portions of memory devices may be described as volatile memory.Examples of volatile memories may include random access memories (RAM),dynamic random access memories (DRAM), and static random access memories(SRAM).

Examples of non-volatile memories may include magnetic hard discs,optical discs, floppy discs, flash memories, or forms of electricallyprogrammable memories (EPROM) or electrically erasable and programmable(EEPROM) memories. Storage device(s) may include memory cards (e.g., aSecure Digital (SD) memory card), internal/external hard disk drives,and/or internal/external solid state drives. Data may be stored on astorage device according to a defined file format.

FIG. 4 is a conceptual drawing illustrating an example of componentsthat may be included in an implementation of system 100. In the exampleimplementation illustrated in FIG. 4, system 100 includes one or morecomputing devices 402A-402N, television service network 404, televisionservice provider site 406, wide area network 408, local area network410, and one or more content provider sites 412A-412N. Theimplementation illustrated in FIG. 4 represents an example of a systemthat may be configured to allow digital media content, such as, forexample, a movie, a live sporting event, etc., and data and applicationsand media presentations associated therewith to be distributed to andaccessed by a plurality of computing devices, such as computing devices402A-402N. In the example illustrated in FIG. 4, computing devices402A-402N may include any device configured to receive data from one ormore of television service network 404, wide area network 408, and/orlocal area network 410. For example, computing devices 402A-402N may beequipped for wired and/or wireless communications and may be configuredto receive services through one or more data channels and may includetelevisions, including so-called smart televisions, set top boxes, anddigital video recorders. Further, computing devices 402A-402N mayinclude desktop, laptop, or tablet computers, gaming consoles, mobiledevices, including, for example, “smart” phones, cellular telephones,and personal gaming devices.

Television service network 404 is an example of a network configured toenable digital media content, which may include television services, tobe distributed. For example, television service network 404 may includepublic over-the-air television networks, public or subscription-basedsatellite television service provider networks, and public orsubscription-based cable television provider networks and/or over thetop or Internet service providers. It should be noted that although insome examples television service network 404 may primarily be used toenable television services to be provided, television service network404 may also enable other types of data and services to be providedaccording to any combination of the telecommunication protocolsdescribed herein. Further, it should be noted that in some examples,television service network 404 may enable two-way communications betweentelevision service provider site 406 and one or more of computingdevices 402A-402N. Television service network 404 may comprise anycombination of wireless and/or wired communication media. Televisionservice network 404 may include coaxial cables, fiber optic cables,twisted pair cables, wireless transmitters and receivers, routers,switches, repeaters, base stations, or any other equipment that may beuseful to facilitate communications between various devices and sites.Television service network 404 may operate according to a combination ofone or more telecommunication protocols. Telecommunications protocolsmay include proprietary aspects and/or may include standardizedtelecommunication protocols. Examples of standardized telecommunicationsprotocols include DVB standards, ATSC standards, ISDB standards, DTMBstandards, DMB standards, Data Over Cable Service InterfaceSpecification (DOCSIS) standards, HbbTV standards, W3C standards, andUPnP standards.

Referring again to FIG. 4, television service provider site 406 may beconfigured to distribute television service via television servicenetwork 404. For example, television service provider site 406 mayinclude one or more broadcast stations, a cable television provider, ora satellite television provider, or an Internet-based televisionprovider. For example, television service provider site 406 may beconfigured to receive a transmission including television programmingthrough a satellite uplink/downlink. Further, as illustrated in FIG. 4,television service provider site 406 may be in communication with widearea network 408 and may be configured to receive data from contentprovider sites 412A-412N. It should be noted that in some examples,television service provider site 406 may include a television studio andcontent may originate therefrom.

Wide area network 408 may include a packet based network and operateaccording to a combination of one or more telecommunication protocols.Telecommunications protocols may include proprietary aspects and/or mayinclude standardized telecommunication protocols. Examples ofstandardized telecommunications protocols include Global System MobileCommunications (GSM) standards, code division multiple access (CDMA)standards, 3rd Generation Partnership Project (3GPP) standards, EuropeanTelecommunications Standards Institute (ETSI) standards, Europeanstandards (EN), IP standards, Wireless Application Protocol (WAP)standards, and Institute of Electrical and Electronics Engineers (IEEE)standards, such as, for example, one or more of the IEEE 802 standards(e.g., Wi-Fi). Wide area network 408 may comprise any combination ofwireless and/or wired communication media. Wide area network 408 mayinclude coaxial cables, fiber optic cables, twisted pair cables,Ethernet cables, wireless transmitters and receivers, routers, switches,repeaters, base stations, or any other equipment that may be useful tofacilitate communications between various devices and sites. In oneexample, wide area network 408 may include the Internet. Local areanetwork 410 may include a packet based network and operate according toa combination of one or more telecommunication protocols. Local areanetwork 410 may be distinguished from wide area network 408 based onlevels of access and/or physical infrastructure. For example, local areanetwork 410 may include a secure home network.

Referring again to FIG. 4, content provider sites 412A-412N representexamples of sites that may provide multimedia content to televisionservice provider site 406 and/or computing devices 402A-402N. Forexample, a content provider site may include a studio having one or morestudio content servers configured to provide multimedia files and/orstreams to television service provider site 406. In one example, contentprovider sites 412A-412N may be configured to provide multimedia contentusing the IP suite. For example, a content provider site may beconfigured to provide multimedia content to a receiver device accordingto Real Time Streaming Protocol (RTSP), HTTP, or the like. Further,content provider sites 412A-412N may be configured to provide data,including hypertext based content, and the like, to one or more ofreceiver devices computing devices 402A-402N and/or television serviceprovider site 406 through wide area network 408. Content provider sites412A-412N may include one or more web servers. Data provided by dataprovider site 412A-412N may be defined according to data formats.

Referring again to FIG. 1, source device 102 includes video source 104,video encoder 106, data encapsulator 107, and interface 108. Videosource 104 may include any device configured to capture and/or storevideo data. For example, video source 104 may include a video camera anda storage device operably coupled thereto. Video encoder 106 may includeany device configured to receive video data and generate a compliantbitstream representing the video data. A compliant bitstream may referto a bitstream that a video decoder can receive and reproduce video datatherefrom. Aspects of a compliant bitstream may be defined according toa video coding standard. When generating a compliant bitstream videoencoder 106 may compress video data. Compression may be lossy(discernible or indiscernible to a viewer) or lossless. FIG. 5 is ablock diagram illustrating an example of video encoder 500 that mayimplement the techniques for encoding video data described herein. Itshould be noted that although example video encoder 500 is illustratedas having distinct functional blocks, such an illustration is fordescriptive purposes and does not limit video encoder 500 and/orsub-components thereof to a particular hardware or softwarearchitecture. Functions of video encoder 500 may be realized using anycombination of hardware, firmware, and/or software implementations.

Video encoder 500 may perform intra prediction coding and interprediction coding of picture areas, and, as such, may be referred to asa hybrid video encoder. In the example illustrated in FIG. 5, videoencoder 500 receives source video blocks. In some examples, source videoblocks may include areas of picture that has been divided according to acoding structure. For example, source video data may includemacroblocks, CTUs, CBs, sub-divisions thereof, and/or another equivalentcoding unit. In some examples, video encoder 500 may be configured toperform additional sub-divisions of source video blocks. It should benoted that the techniques described herein are generally applicable tovideo coding, regardless of how source video data is partitioned priorto and/or during encoding. In the example illustrated in FIG. 5, videoencoder 500 includes summer 502, transform coefficient generator 504,coefficient quantization unit 506, inverse quantization and transformcoefficient processing unit 508, summer 510, intra prediction processingunit 512, inter prediction processing unit 514, filter unit 516, andentropy encoding unit 518. As illustrated in FIG. 5, video encoder 500receives source video blocks and outputs a bitstream.

In the example illustrated in FIG. 5, video encoder 500 may generateresidual data by subtracting a predictive video block from a sourcevideo block. The selection of a predictive video block is described indetail below. Summer 502 represents a component configured to performthis subtraction operation. In one example, the subtraction of videoblocks occurs in the pixel domain. Transform coefficient generator 504applies a transform, such as a discrete cosine transform (DCT), adiscrete sine transform (DST), or a conceptually similar transform, tothe residual block or sub-divisions thereof (e.g., four 8×8 transformsmay be applied to a 16×16 array of residual values) to produce a set ofresidual transform coefficients. Transform coefficient generator 504 maybe configured to perform any and all combinations of the transformsincluded in the family of discrete trigonometric transforms, includingapproximations thereof. Transform coefficient generator 504 may outputtransform coefficients to coefficient quantization unit 506. Coefficientquantization unit 506 may be configured to perform quantization of thetransform coefficients. The quantization process may reduce the bitdepth associated with some or all of the coefficients. The degree ofquantization may alter the rate-distortion (i.e., bit-rate vs. qualityof video) of encoded video data. The degree of quantization may bemodified by adjusting a quantization parameter (QP). A quantizationparameter may be determined based on slice level values and/or CU levelvalues (e.g., CU delta QP values). QP data may include any data used todetermine a QP for quantizing a particular set of transformcoefficients. As illustrated in FIG. 5, quantized transform coefficients(which may be referred to as level values) are output to inversequantization and transform coefficient processing unit 508. Inversequantization and transform coefficient processing unit 508 may beconfigured to apply an inverse quantization and an inversetransformation to generate reconstructed residual data. As illustratedin FIG. 5, at summer 510, reconstructed residual data may be added to apredictive video block. In this manner, an encoded video block may bereconstructed and the resulting reconstructed video block may be used toevaluate the encoding quality for a given prediction, transformation,and/or quantization. Video encoder 500 may be configured to performmultiple coding passes (e.g., perform encoding while varying one or moreof a prediction, transformation parameters, and quantizationparameters). The rate-distortion of a bitstream or other systemparameters may be optimized based on evaluation of reconstructed videoblocks. Further, reconstructed video blocks may be stored and used asreference for predicting subsequent blocks.

Referring again to FIG. 5, intra prediction processing unit 512 may beconfigured to select an intra prediction mode for a video block to becoded. Intra prediction processing unit 512 may be configured toevaluate a frame and determine an intra prediction mode to use to encodea current block. As described above, possible intra prediction modes mayinclude planar prediction modes, DC prediction modes, and angularprediction modes. Further, it should be noted that in some examples, aprediction mode for a chroma component may be inferred from a predictionmode for a luma prediction mode. Intra prediction processing unit 512may select an intra prediction mode after performing one or more codingpasses. Further, in one example, intra prediction processing unit 512may select a prediction mode based on a rate-distortion analysis. Asillustrated in FIG. 5, intra prediction processing unit 512 outputsintra prediction data (e.g., syntax elements) to entropy encoding unit518 and transform coefficient generator 504. As described above, atransform performed on residual data may be mode dependent (e.g., asecondary transform matrix may be determined based on a predictionmode).

Referring again to FIG. 5, inter prediction processing unit 514 may beconfigured to perform inter prediction coding for a current video block.Inter prediction processing unit 514 may be configured to receive sourcevideo blocks and calculate a motion vector for PUs of a video block. Amotion vector may indicate the displacement of a PU of a video blockwithin a current video frame relative to a predictive block within areference frame. Inter prediction coding may use one or more referencepictures. Further, motion prediction may be uni-predictive (use onemotion vector) or bi-predictive (use two motion vectors). Interprediction processing unit 514 may be configured to select a predictiveblock by calculating a pixel difference determined by, for example, sumof absolute difference (SAD), sum of square difference (SSD), or otherdifference metrics. As described above, a motion vector may bedetermined and specified according to motion vector prediction. Interprediction processing unit 514 may be configured to perform motionvector prediction, as described above. Inter prediction processing unit514 may be configured to generate a predictive block using the motionprediction data. For example, inter prediction processing unit 514 maylocate a predictive video block within a frame buffer (not shown in FIG.5). It should be noted that inter prediction processing unit 514 mayfurther be configured to apply one or more interpolation filters to areconstructed residual block to calculate sub-integer pixel values foruse in motion estimation. Inter prediction processing unit 514 mayoutput motion prediction data for a calculated motion vector to entropyencoding unit 518.

Referring again to FIG. 5, filter unit 516 receives reconstructed videoblocks and coding parameters and outputs modified reconstructed videodata. Filter unit 516 may be configured to perform deblocking and/orSample Adaptive Offset (SAO) filtering. SAO filtering is a non-linearamplitude mapping that may be used to improve reconstruction by addingan offset to reconstructed video data. It should be noted that asillustrated in FIG. 5, intra prediction processing unit 512 and interprediction processing unit 514 may receive modified reconstructed videoblock via filter unit 216. Entropy encoding unit 518 receives quantizedtransform coefficients and predictive syntax data (i.e., intraprediction data and motion prediction data). It should be noted that insome examples, coefficient quantization unit 506 may perform a scan of amatrix including quantized transform coefficients before thecoefficients are output to entropy encoding unit 518. In other examples,entropy encoding unit 518 may perform a scan. Entropy encoding unit 518may be configured to perform entropy encoding according to one or moreof the techniques described herein. In this manner, video encoder 500represents an example of a device configured to generate encoded videodata according to one or more techniques of this disclosure.

Referring again to FIG. 1, data encapsulator 107 may receive encodedvideo data and generate a compliant bitstream, e.g., a sequence of NALunits according to a defined data structure. A device receiving acompliant bitstream can reproduce video data therefrom. Further, asdescribed above, sub-bitstream extraction may refer to a process where adevice receiving a ITU-T H.265 compliant bitstream forms a new ITU-TH.265 compliant bitstream by discarding and/or modifying data in thereceived bitstream. It should be noted that the term conformingbitstream may be used in place of the term compliant bitstream. In oneexample, data encapsulator 107 may be configured to generate syntaxaccording to one or more techniques described herein. It should be notedthat data encapsulator 107 need not necessary be located in the samephysical device as video encoder 106. For example, functions describedas being performed by video encoder 106 and data encapsulator 107 may bedistributed among devices illustrated in FIG. 4.

As described above, JVET-O2001 does not define an Annex A. Table 5provides examples of profiles, levels, and tiers which may be usedaccording to the techniques herein.

[Object 19]

TABLE 5 Tier and level limits for the Main and Main 10 profiles Max lumasample Max bit rate MaxBR Min rate MaxLumaSr (1000 bits/s) CompressionLevel (samples/sec) Main tier High tier Ratio MinCr 1      552 960   128 — 2 2    3 686 400  1 500 — 2 2.1    7 372 800  3 000 — 2 3   16 588800  6 000 — 2 3.1   33 177 600  10 000 — 2 4   66 846 720  12 000  30000 4 4.1   133 693 440  20 000  50 000 4 5   267 386 880  25 000 100000 6 5.1   534 773 760  40 000 160 000 8 5.2 1 069 547 520  60 000 240000 8 6 1 069 547 520  60 000 240 000 8 6.1 2 139 095 040 120 000 480000 8

[Object 20]

As further described above, the signaling of the general level of a CVStn JVET-O2001 is less than ideal. In one example, according to thetechniques herein, syntax element general_level_idc is moved to precedesyntax element num_sub_profile in the profile_tier_level( ) syntaxstructure. Table 6 and Table 7 illustrate examples where syntax elementgeneral_level_idc is moved to precede syntax element num_sub_profile inthe profile_tier_level( ) syntax structure. It should lie noted thatwith general_level_idc preceding num_sub_profile in the syntax, thevalue of general_level_idc can be determined without parsing syntaxelements which are conditionally present based on the value ofnum_sub_profile.

[Object 21]

-   -   As provided above, the general_constraint_info( ) is a fixed        length syntax structure with no conditionally present syntax        elements. In the example in Table 7, the        general_constraint_info( ) syntax structure is also moved before        the conditionally present syntax elements related to        num_sub_profiles. In another example, the        general_constraint_info( ) syntax structure may be placed after        general_level_idc instead of before it. One benefit of moving        the general_constraint_info( ) syntax structure in this manner        is that general_constraint_info( ) can be parsed without parsing        syntax elements which are conditionally present based on the        value of num_sub_profile.

TABLE 6 Descriptor profile_tier_level( maxNumSubLayersMinus1 ) { general_profile_idc u(7)  general_tier_flag u(1)  general_level_idcu(8)  num_sub_profiles u(8)  for( i = 0; i < num_sub_profiles; i++ )  general_sub_profiles_idc[ i ]  u(32)  general_constraint_info( )  for(i = 0; i < maxNumSubLayersMinus1; i++ )   sub_layer_level_present_flag[i ] u(1)  while( !byte_aligned( ) )   ptl_alignment_zero_bit f(1)  for(i = 0; i < maxNumSubLayersMinus1; i++ )   if(sub_layer_level_present_flag[ i ] )    sub_layer_level_idc[ i ] u(8) }

[Object 22]

TABLE 7 Descriptor profile_tier_level( maxNumSubLayersMinus1 ) { general_profile_idc u(7)  general_tier_flag u(1) general_constraint_info( )  general_level_idc u(8)  num_sub_profilesu(8)  for( i = 0; i < num_sub_profiles; i++ )  general_sub_profiles_idc[ i ]  u(32)  for( i = 0; i <maxNumSubLayersMinus1; i++ )   sub_layer_level_present_flag[ i ] u(1) while( !byte_aligned( ) )   ptl_alignment_zero_bit f(1)  for( i = 0; i< maxNumSubLayersMinus1; i++ )   if( sub_layer_level_present_flag[ i ] )   sub_layer_level_idc[ i ] u(8) }

With respect to Table 6 and Table 7, compared to JVET-O2001, the forloop for signaling general_sub_profile_idc[i] may be changed fromfor(i=0; i<=num_sub_profiles; i++) in JVET-O2001 to for(i=0;i<num_sub_profiles; i++). This allows a profile_tier_level structurewhich can signal a zero value for num_sub_profiles and in that case notinclude any general_sub_profile_idc[i] syntax elements. This allowsspecifying only the general_profile_idc, general_tier_flag,general_constraint_info( ), and general_level_idc and not specifying anysub-profile information. This may be useful when the bitstream does notcater to sub-profiles. In this case, the above change in the for loopsaves bits.

[Object 23]

-   -   With respect to Table 6 and Table 7, in one example the        semantics may be based on the semantics provided above with        respect to Table 4. Further, in one example, the semantic s may        be based on the following, where sub_layer_level_idc may be        inferred:    -   When the profile_tier_level( ) structure is included in a DPS,        the BitstreamInScope is die entire bitstream that refers to the        DPS. When the profile_tier_level( ) structure is included in an        SPS, the BitstreamInScope is the CVS that refers to the SPS.    -   general_profile_idc indicates a profile to which        BitstreamInScope conforms as specified in Annex A. Bitstreams        shall not contain values of general_profile_idc other than those        specified in Annex A. Other values of general_profile_idc are        reserved for future use by ITU-T|ISO/TEC.    -   general_tier_flag specifies the tier context for the        interpretation of general_level_idc as specified in Annex A.    -   num_sub_profiles raffles specifies the number of die        general_sub_profile_idc[i] syntax elements.    -   general_sub_profile_idc[i] indicates the i-th interoperability        metadata registered as specified by X Recommendation ITU-T T.35,        the contents of which are not specified in this Specification.

[Object 24]

-   -   general_level_idc indicates a level to which BitstresmInScope        conforms as specified in Annex A. Bitstreams shall not contain        values of general_level_idc other than those specified in        Annex A. Other values of general_level_idc are reserved for        future, use by ITU-T|ISO/IEC.    -   NOTE—A greater value of general_level_idc indicates a higher        level. The maximum level signalled in the DPS for        BitstreamInScope may be higher than die level signalled in the        SPS for a CVS contained within BitstreamInScope.    -   NOTE—When BitstreamInScope conforms to multiple profiles,        general_profile_idc should indicate the profile that provides        the preferred decoded result or the preferred bitstream        identification, as determined by the encoder (in a manner not        specified in this Specification).    -   NOTE—When tire profile_tier_level( ) syntax structure is        included in a DPS and CVSs of BitstreamInScope conform to        different profiles, general_profile_idc and level_idc should        indicate the profile and level for a decoder that is capable of        decoding BitstreamInScope.    -   sub_layer_level_present_flag[i] equal to 1 specifies that level        information is present in the profile_tier_level( ) syntax        structure for the sub-layer representation with TemporalID equal        to i. sub_layer_level_present_flag[i] equal to 0 specifies that        level information is not present in foe profile_tier_level( )        syntax structure for the sub-layer representation with        TemporalId equal to i.    -   ptI_alignment_zero_bits shall be equal to 0.    -   The semantics, of the syntax element sub_layer_level_idc[i] is,        apart from the specification of the inference of not present        values, the same as the syntax element general_level_idc, but        apply to die sub-layer representation with TemporalId equal to        i.

[Object 25]

-   -   For profile_tier_level( ) syntax structure included in DPS and        SPS, when, not present sub_layer_level_idc[t] is inferred as        follows:        -   sub_layer_level_idc[maxNumSubLayersMinus1] is inferred to be            equal to general_level_idc of the same profile_tier_level( )            structure,        -   for i in the range of maxNumSubLayersMinus1−1 to 0 (in            decreasing order of i values), sub_layer_level_idc[i] is            inferred to be equal to sub_layer_level_idc[i+1] of the same            profile_tier_level( ) structure,    -   In another example, the above inference may be specified as        follows:    -   When not present sub_layer_level_idc[i] is inferred as follows:        -   sub_layer_level_idc[maxNumSubLayersMinus1] is infested to be            equal to general_level_idc of the same profile_tier_level( )            structure.        -   tor i in the range of maxNumSubLayersMinus1−1 to 0 (in            decreasing order of i values), sub_layer_level_idc[i] is            inferred to be equal to sub_layer_level_idc[i+1].

[Object 26]

-   -   Further, m one example, in one or more of the    -   profile_tier_level(maxNumSubLayersMinus1) syntax structures        above, the value range of syntax element num_sub_profiles may be        reduced, for example, 0-4, 0-8 or 0-16, inclusive. In one        example, a reduction of the value range of syntax element        num_sub_profiles, according to the techniques herein, may be        accomplished by introducing a semantics constraint such as; “The        value of num_sub_profiles shall be in the range of 0 to 8,        inclusive.” In one example, it may be preferable to keeps syntax        element num_sub_profiles signalled as an 8-bit value in order to        keep the syntax elements byte aligned and allow for a        possibility to increase the value range in a future        implementations.

[Object 27]

-   -   It should be noted that when syntax, element num_snb_profiles is        seduced in the case of the syntax of Table 4, although parsing        general_level_idc would still require parsing or jumping by a        number of 32-bit values, the reduction would reduce tire worst        case length of such parsing or jumping. It should be noted th at        when the value range of syntax, element num_sub_profiles is be        reduced with respect to Table 6 and Table 7, tins may ensure        that the size of the syntax structure does not become too large        and that syntax elements following the 32-bit values can fee        accessed without requiring too much processing.

In this manner, source device 102 represents an example of a deviceconfigured to signal a syntax element indicating a profile correspondingto a coded video sequence, signal a syntax element indicating a contextcorresponding to the coded video sequence, and signal a syntax elementindicating a level corresponding to the coded video sequence, whereinthe syntax element indicating the level immediately follows the syntaxelement indicating the context.

Referring again to FIG. 1, interface 108 may include any deviceconfigured to receive data generated by data encapsulator 107 andtransmit and/or store the data to a communications medium. Interface 108may include a network interface card, such as an Ethernet card, and mayinclude an optical transceiver, a radio frequency transceiver, or anyother type of device that can send and/or receive information. Further,interface 108 may include a computer system interface that may enable afile to be stored on a storage device. For example, interface 108 mayinclude a chipset supporting Peripheral Component Interconnect (PCI) andPeripheral Component Interconnect Express (PCIe) bus protocols,proprietary bus protocols, Universal Serial Bus (USB) protocols, I²C, orany other logical and physical structure that may be used tointerconnect peer devices.

Referring again to FIG. 1, destination device 120 includes interface122, data decapsulator 123, video decoder 124, and display 126.Interface 122 may include any device configured to receive data from acommunications medium. Interface 122 may include a network interfacecard, such as an Ethernet card, and may include an optical transceiver,a radio frequency transceiver, or any other type of device that canreceive and/or send information. Further, interface 122 may include acomputer system interface enabling a compliant video bitstream to beretrieved from a storage device. For example, interface 122 may includea chipset supporting PCI and PCIe bus protocols, proprietary busprotocols, USB protocols, I²C, or any other logical and physicalstructure that may be used to interconnect peer devices. Datadecapsulator 123 may be configured to receive and parse any of theexample syntax structures described herein.

Video decoder 124 may include any device configured to receive abitstream (e.g., a sub-bitstream extraction) and/or acceptablevariations thereof and reproduce video data therefrom. Display 126 mayinclude any device configured to display video data. Display 126 maycomprise one of a variety of display devices such as a liquid crystaldisplay (LCD), a plasma display, an organic light emitting diode (OLED)display, or another type of display. Display 126 may include a HighDefinition display or an Ultra High Definition display. It should benoted that although in the example illustrated in FIG. 1, video decoder124 is described as outputting data to display 126, video decoder 124may be configured to output video data to various types of devicesand/or sub-components thereof. For example, video decoder 124 may beconfigured to output video data to any communication medium, asdescribed herein.

FIG. 6 is a block diagram illustrating an example of a video decoderthat may be configured to decode video data according to one or moretechniques of this disclosure (e.g., the decoding process forreference-picture list construction described above). In one example,video decoder 600 may be configured to decode transform data andreconstruct residual data from transform coefficients based on decodedtransform data. Video decoder 600 may be configured to perform intraprediction decoding and inter prediction decoding and, as such, may bereferred to as a hybrid decoder. Video decoder 600 may be configured toparse any combination of the syntax elements described above in Tables1-7. Video decoder 600 may decode a picture based on or according to theprocesses described above, and further based on parsed values in Tables1-7.

In the example illustrated in FIG. 6, video decoder 600 includes anentropy decoding unit 602, inverse quantization unit 604, inversetransform processing unit 606, intra prediction processing unit 608,inter prediction processing unit 610, summer 612, post filter unit 614,and reference buffer 616. Video decoder 600 may be configured to decodevideo data in a manner consistent with a video coding system. It shouldbe noted that although example video decoder 600 is illustrated ashaving distinct functional blocks, such an illustration is fordescriptive purposes and does not limit video decoder 600 and/orsub-components thereof to a particular hardware or softwarearchitecture. Functions of video decoder 600 may be realized using anycombination of hardware, firmware, and/or software implementations.

As illustrated in FIG. 6, entropy decoding unit 602 receives an entropyencoded bitstream. Entropy decoding unit 602 may be configured to decodesyntax elements and quantized coefficients from the bitstream accordingto a process reciprocal to an entropy encoding process. Entropy decodingunit 602 may be configured to perform entropy decoding according any ofthe entropy coding techniques described above. Entropy decoding unit 602may determine values for syntax elements in an encoded bitstream in amanner consistent with a video coding standard. As illustrated in FIG.6, entropy decoding unit 602 may determine a quantization parameter,quantized coefficient values, transform data, and prediction data from abitstream. In the example, illustrated in FIG. 6, inverse quantizationunit 604 and inverse transform processing unit 606 receives aquantization parameter, quantized coefficient values, transform data,and prediction data from entropy decoding unit 602 and outputsreconstructed residual data.

Referring again to FIG. 6, reconstructed residual data may be providedto summer 612. Summer 612 may add reconstructed residual data to apredictive video block and generate reconstructed video data. Apredictive video block may be determined according to a predictive videotechnique (i.e., intra prediction and inter frame prediction). Intraprediction processing unit 608 may be configured to receive intraprediction syntax elements and retrieve a predictive video block fromreference buffer 616. Reference buffer 616 may include a memory deviceconfigured to store one or more frames of video data. Intra predictionsyntax elements may identify an intra prediction mode, such as the intraprediction modes described above. Inter prediction processing unit 610may receive inter prediction syntax elements and generate motion vectorsto identify a prediction block in one or more reference frames stored inreference buffer 616. Inter prediction processing unit 610 may producemotion compensated blocks, possibly performing interpolation based oninterpolation filters. Identifiers for interpolation filters to be usedfor motion estimation with sub-pixel precision may be included in thesyntax elements. Inter prediction processing unit 610 may useinterpolation filters to calculate interpolated values for sub-integerpixels of a reference block. Post filter unit 614 may be configured toperform filtering on reconstructed video data. For example, post filterunit 614 may be configured to perform deblocking and/or Sample AdaptiveOffset (SAO) filtering, e.g., based on parameters specified in abitstream. Further, it should be noted that in some examples, postfilter unit 614 may be configured to perform proprietary discretionaryfiltering (e.g., visual enhancements, such as, mosquito noisereduction). As illustrated in FIG. 6, a reconstructed video block may beoutput by video decoder 600. In this manner, video decoder 600represents an example of a device configured to parse a syntax elementindicating a profile corresponding to a coded video sequence, parse asyntax element indicating a context corresponding to the coded videosequence, and parse a syntax element indicating a level corresponding tothe coded video sequence, wherein the syntax element indicating thelevel immediately follows the syntax element indicating the context.

In one or more examples, the functions described may be implemented inhardware, software, firmware, or any combination thereof. If implementedin software, the functions may be stored on or transmitted over as oneor more instructions or code on a computer-readable medium and executedby a hardware-based processing unit.

Computer-readable media may include computer-readable storage media,which corresponds to a tangible medium such as data storage media, orcommunication media including any medium that facilitates transfer of acomputer program from one place to another, e.g., according to acommunication protocol. In this manner, computer-readable mediagenerally may correspond to (1) tangible computer-readable storage mediawhich is non-transitory or (2) a communication medium such as a signalor carrier wave. Data storage media may be any available media that canbe accessed by one or more computers or one or more processors toretrieve instructions, code and/or data structures for implementation ofthe techniques described in this disclosure. A computer program productmay include a computer-readable medium.

By way of example, and not limitation, such computer-readable storagemedia can comprise RAM, ROM, EEPROM, CD-ROM or other optical diskstorage, magnetic disk storage, or other magnetic storage devices, flashmemory, or any other medium that can be used to store desired programcode in the form of instructions or data structures and that can beaccessed by a computer. Also, any connection is properly termed acomputer-readable medium. For example, if instructions are transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, digital subscriber line (DSL), orwireless technologies such as infrared, radio, and microwave, then thecoaxial cable, fiber optic cable, twisted pair, DSL, or wirelesstechnologies such as infrared, radio, and microwave are included in thedefinition of medium. It should be understood, however, thatcomputer-readable storage media and data storage media do not includeconnections, carrier waves, signals, or other transitory media, but areinstead directed to non-transitory, tangible storage media. Disk anddisc, as used herein, includes compact disc (CD), laser disc, opticaldisc, digital versatile disc (DVD), floppy disk and Blu-ray disc wheredisks usually reproduce data magnetically, while discs reproduce dataoptically with lasers. Combinations of the above should also be includedwithin the scope of computer-readable media.

Instructions may be executed by one or more processors, such as one ormore digital signal processors (DSPs), general purpose microprocessors,application specific integrated circuits (ASICs), field programmablelogic arrays (FPGAs), or other equivalent integrated or discrete logiccircuitry. Accordingly, the term “processor,” as used herein may referto any of the foregoing structure or any other structure suitable forimplementation of the techniques described herein. In addition, in someaspects, the functionality described herein may be provided withindedicated hardware and/or software modules configured for encoding anddecoding, or incorporated in a combined codec. Also, the techniquescould be fully implemented in one or more circuits or logic elements.

The techniques of this disclosure may be implemented in a wide varietyof devices or apparatuses, including a wireless handset, an integratedcircuit (IC) or a set of ICs (e.g., a chip set). Various components,modules, or units are described in this disclosure to emphasizefunctional aspects of devices configured to perform the disclosedtechniques, but do not necessarily require realization by differenthardware units. Rather, as described above, various units may becombined in a codec hardware unit or provided by a collection ofinteroperative hardware units, including one or more processors asdescribed above, in conjunction with suitable software and/or firmware.

Moreover, each functional block or various features of the base stationdevice and the terminal device used in each of the aforementionedembodiments may be implemented or executed by a circuitry, which istypically an integrated circuit or a plurality of integrated circuits.The circuitry designed to execute the functions described in the presentspecification may comprise a general-purpose processor, a digital signalprocessor (DSP), an application specific or general applicationintegrated circuit (ASIC), a field programmable gate array (FPGA), orother programmable logic devices, discrete gates or transistor logic, ora discrete hardware component, or a combination thereof. Thegeneral-purpose processor may be a microprocessor, or alternatively, theprocessor may be a conventional processor, a controller, amicrocontroller or a state machine. The general-purpose processor oreach circuit described above may be configured by a digital circuit ormay be configured by an analogue circuit. Further, when a technology ofmaking into an integrated circuit superseding integrated circuits at thepresent time appears due to advancement of a semiconductor technology,the integrated circuit by this technology is also able to be used.

Various examples have been described. These and other examples arewithin the scope of the following claims.

SUMMARY

In one example, a method of signaling level information for video data,the method comprising: signaling a syntax element indicating a profilecorresponding to a coded video sequence; signaling a syntax elementindicating a context corresponding to the coded video sequence; andsignaling a syntax element indicating a level corresponding to the codedvideo sequence, wherein the syntax element indicating the levelimmediately follows the syntax element indicating the context.

In one example, a method of decoding video data, the method comprising:parsing a syntax element indicating a profile corresponding to a codedvideo sequence; parsing a syntax element indicating a contextcorresponding to the coded video sequence; and parsing a syntax elementindicating a level corresponding to the coded video sequence, whereinthe syntax element indicating the level immediately follows the syntaxelement indicating the context.

In one example, the method, wherein the syntax elements are included ina profile tier level syntax structure.

In one example, a device comprising one or more processors configured toperform any and all combinations of the steps.

In one example, the device, wherein the device includes a video encoder.

In one example, the device, wherein the device includes a video decoder.

In one example, a system comprising: the device includes a videoencoder; and the device includes a video decoder.

In one example, an apparatus comprising means for performing any and allcombinations of the steps.

In one example, a non-transitory computer-readable storage mediumcomprising instructions stored thereon that, when executed, cause one ormore processors of a device to perform any and all combinations of thesteps.

In one example, a method of signaling level information for video data,the method comprising: signaling a first syntax element indicating aprofile; signaling a second syntax element indicating a context;signaling a third syntax element indicating a level; sending a profiletier level syntax structure including the first syntax element, secondsyntax element and third syntax element, wherein the first syntaxelement, the second syntax element and the third syntax element arelocated on a top of the profile tier level syntax structure, and whereinthe third syntax element immediately follows the second syntax element.

In one example, a method of decoding video data, the method comprising:receiving a profile tier level syntax structure; parsing a first syntaxelement, from the profile tier level syntax structure, indicating aprofile; parsing a second syntax element, from the profile tier levelsyntax structure, indicating a context; and parsing a third syntaxelement, from the profile tier level syntax structure, indicating alevel, wherein the first syntax element, the second syntax element andthe third syntax element are located on a top of the profile tier levelsyntax structure, and wherein the third syntax element immediatelyfollows the second syntax element.

In one example, the method, further comprising: for indices in a rangeof 0 to a maximum number of sub-layers minus 2, determining whether ornot a fourth syntax element, with an index, indicating level informationfor a sub-layer is present; and in a case that the fourth syntax elementwith an index i is not present, inferring a value of the fourth syntaxelement with the index i equal to a value of the fourth syntax elementwith an index (i+1).

In one example, a device of decoding video data, the device comprisingone or more processors configured to: receive a profile tier levelsyntax structure; parse a first syntax element, from the profile tierlevel syntax structure, indicating a profile; parse a second syntaxelement, from the profile tier level syntax structure, indicating acontext; and parse a third syntax element, from the profile tier levelsyntax structure, indicating a level, wherein the first syntax element,the second syntax element and the third syntax element are located on atop of the profile tier level syntax structure, and wherein the thirdsyntax element immediately follows the second syntax element.

CROSS REFERENCE

This Nonprovisional application claims priority under 35 U.S.C. § 119 onprovisional Application No. 62/897,149 on Sep. 6, 2019, the entirecontents of which are hereby incorporated by reference.

1. A method of decoding video data, the method comprising: receiving aprofile tier level syntax structure included in a sequence parameterset; parsing a first syntax element, from the profile tier level syntaxstructure, indicating whether or not a level information for a sub-layeris present in the profile tier level syntax structure; parsing a secondsyntax element, from the profile tier level syntax structure, indicatingthe level information for the sub-layer with a sub-layer index in arange of 0 to a maximum number of sub-layers minus 2 based on the firstsyntax element; and in a case that the second syntax element with anindex i is not present, inferring a value of the second syntax elementwith the index i equal to a value of the second syntax element with anindex (i+1).
 2. A device of decoding video data, the device comprisingone or more processors configured to: receive a profile tier levelsyntax structure included in a sequence parameter set; parse a firstsyntax element, from the profile tier level syntax structure, indicatingwhether or not a level information for a sub-layer is present in theprofile tier level syntax structure; parse a second syntax element, fromthe profile tier level syntax structure, indicating the levelinformation for the sub-layer with a sub-layer index in a range of 0 toa maximum number of sub-layers minus 2 based on the first syntaxelement; and in a case that the second syntax element with an index i isnot present, infer a value of the second syntax element with the index iequal to a value of the second syntax element with an index (i+1).